1. Field of the Invention
The present invention relates to a multi-mode scheduler, an apparatus including a multi-mode scheduler and a multi-mode scheduling method and more particularly to a scheduler used for a communication infrastructure and controlling an input buffer switch.
The present application claims priority of Japanese Patent Application No. 2000-031347 filed on Feb. 9, 2000, which is hereby incorporated by reference.
2. Description of the Prior Art
As an internet has come into wide use drastically, a drastic change of a public infrastructure has been required, and there fore, there is a growing tendency for the internet to be used as a communication infrastructure.
In order to use the internet as the communication infrastructure, it is necessary to provide extendibility of service nodes (routers) in accordance with an increment of traffic and to provide a plurality of service qualities, and it is also necessary for a scheduler to deal with two requirements.
As a technique carrying out a switch of the router as the communication infrastructure, an input buffer switch using a VOQ (Virtual Output Queuing) has an advantage.
As a technique carrying out the extendibility, there is a technique discussed in Electronic Communication Society Technical Research Report (SSE99-121, Dec. 16, 1999). As a technique providing the plurality of service qualities, there is a technique discussed in Electronic Communication Society Technical Research Report (SSE99-120, Dec. 16, 1999). However, these reports deal with either the extendibility or the plurality of service qualities.
In a conventional scheduler, when the internet is used as the communication infrastructure, it is required to cope with the extendibility of service nodes (routers) in accordance with the increment of traffic and to provide the plurality of service qualities. Generally, extendibility is required for a base router and the plurality of service qualities is required for a subscriber router.
However, any conventional schedulers which serve extendibility cannot serve the plurality of service qualities. In contract, any another conventional schedulers which serve the plurality of service qualities cannot serve extendibility.